In a small-scaled, self-propelled machine such as a self-propelled floor-cleaning machine or the like, a mechanism for braking or locking a drive wheel so as to prevent the travel of the machine is generally associated with the wheel itself. For example, there is disclosed in U.S. Pat. No. 4,380,844 a self-propelled floor-cleaning machine in which a pair of left and right parking brakes adapted for use also for machine-steering purposes are associated with left and right drive wheels. The brake of each side comprises a brake drum of a large diameter, which is formed integrally with a wheel hub at an inner side of the hub, and a brake shoe which may be engaged frictionally to the outer surface of the brake drum. A single control means is provided and permits operation of the brakes of both sides at a same time. In U.S. Pat. No. 3,200,907, there is disclosed a fork lift vehicle in which a positive parking brake is associated with a drive wheel of one side. This parking brake comprises a disc which is fixedly secured to a wheel hub using bolts. The disc includes in its outer peripheral surface a plurality of teeth to which a pawl on an end of a pivotally supported pawl element may be engaged.
In a self-propelled machine having a transaxle which comprises left and right wheel axles, the structure that a parking brake is associated with requires the brake to be assembled separately from the transaxle. This will heighten, in conjunction with the fact that this kind of brake is composed of a relatively large number of parts or elements, the manufacturing cost of the machine. Further, because such parking brake is exposed to an outside of the machine at a location near to the wheel on the ground, it is subject to influences of foreign matters such as rubbish lying about on the ground or floor, especially foreign matters carried or stirred up by the rotating wheel, so that the brake has problems in operation and in durability.
Accordingly, an object of the present invention is to provide a novel transaxle assembly having an axle-locking mechanism which makes assembling of a self-propelled machine easier so as to lower the manufacturing cost of the machine. An attendant object is to provide an axle-locking mechanism of a simple structure so as to lower the manufacturing cost further.
Another object of the present invention is to provide a novel transaxle assembly for self-propelled machines in which an axle-locking mechanism is provided so as to be shut off from the outside of a self-propelled machine so that a high reliability in operation and high durability of the locking mechanism are assured.